The major objectives of the proposed research are to assess how children choose the content of their fantasy play and to develop a more systematic and precise observational measure of fantasy levels in the free play of preschool children than is presently available. The reliability of the observational technique will be assessed for interobserver agreement, test-retest stability (across play sessions), and internal consistency between the components of fantasy that will be observed (in children's use of themes, characters, and props). The validity of the measures will be assessed by determining if fantasy play levels will differentiate between children in terms of their activity preferences, including amount and type of television viewing and fantasy exposure, and parental variables--such as attitudes and practices relating to children play. Age and sex differences will also be assessed. Such an assessment technique will help establish a normative basis of fantasy level in play to be used for later assessments of developmental change and the functions of high fantasy play in children of different ages and with various psychological problems. Thus, this research will provide a foundation for a subsequent research program, particularly in assessing children's choices of symbolic play activities in terms of the functions for the child. This research is relevant to the missions of NIMH, Behavioral Sciences Research, in several ways: (1) it includes an assessment of personality development and social competence; (2) it includes an assessment of individual differences in terms of some early experiences and family processes; (3) it will contribute to an understanding of mental health and illness by clarifying how fantasy play is used by children and allowing mental health workers to have more insight into modifying the type and timing of interventions using play therapy and play training.